As others passed the charred but clearly recognisable remains without so much as a glance, Mr Miguel, a sand lorry driver, said that crime in the area had become very serious.

"We have a lot of robbers round here now. The thieves were just in town before but in the past couple of days they've been coming here."

Although it was impossible to confirm his claim, he said that a trader had had his throat cut in the main square during a robbery. "Everyone's scared," he added.

While still sporadic, violence is occurring with growing frequency across the city as citizens grow increasingly desperate.

Residents in the Del Mar area on Sunday caught two suspected looters, tied them together, beat them unconscious and dragged them through the streets.

The looting has not always been motivated by hunger or thirst. In one of the city's main commercial streets, heavily-outnumbered police fired on looters armed with machetes and sharpened pieces of woods as they fought with each other over goods such as pots and rolls of fabric looted from stores.

As many in the city, both aid agency staff and local people, complain bitterly about America's apparent determination to bring in soldiers before rescue and relief workers, Lieut Gen Ken Keen of the US Southern Command confirmed on Sunday that fear of crime was hampering the relief effort.

While he conceded the streets remained largely peaceful, delivering humanitarian aid required a safe and secure environment, he added.

Such concerns evoke little sympathy from the people waiting for aid. "I understand these people are worried about the risks of bringing aid to us, you cannot save us if you cannot save yourself," said the Rev Paul Frantz Cole as he finished taking morning service at his Anglican church in the Carrefour district.

"The Americans need to go quicker. If they don't deliver food aid, we will have riots," he said. "If the people don't get food, they will have reason to give vent to the violence inside all of us."

Lt Gen Keen said that about 1,000 US troops were already in Haiti and that a further 3,000 more are working from ships offshore.

He said that more than 12,000 US servicemen were expected to be in the region by Monday.

However, there was no sign of American troops on the streets of Port-au-Prince on Sunday, although US helicopters regularly clattered overhead.